Mucus lines and protects both the gastrointestinal tract and the airways of the lungs. This project proposes to investigate the effects of ethanol, at concentrations commonly found in man, on themucus of the small intestine and on tracheal mucus. Ethanol will be administered intravenously in anaesthetized rabbits and rats and the secretion of mucus into the intestinal lumen will be measured, and the mucus blanket examined following stimulation of mucus secretion by a). a cholinergic agonist, b). an elevation in tissue cyclic AMP levels, and c). direct mucosal irritation with allyl isothiocyanate or with ethanol itself. The results of these experiments will allow some definition of the degree to which acute alcohol administration may impair the protection of the intestinal mucosa provided by its mucus blanket. Isolated tracheal mucus and a polysaccharide mucus model will be exposed to flowing air saturated with water vapor, with and without ethanol vapor equivalent to blood ethanol concentrations of 100 and 200 mg%. The viscosity, elasticity, reversible shear-thinning and load bearing capacity of these mucus samples will be measured. These samples will also be measured for their capacity to be moved when placed on h ciliated epithelium of the frog palate. This amphibian system provides a simple model of lung mucociliary clearance. By comparing the rheological effects of ethanol on the isolated mucus with the effects on mucociliary clearance by frog palate we will be able to determine whether or not ethanol can directly affect mucociliary clearance by altering the physical properties of mucus.